Method of combating gastropods



United States Patent ()fifice 3,079,297 Patented Feb. 26, 1963 3,679,297 B/TETHGD F CQMBATTNG GASTRGPODS Ernst Schraufstattcr and Rudolf Gonnert, Wuppertai- Elberield, Germany, assignors to Farbentahriken Bayer Aktiengesellschaft, Leverkusen, Germany, a German corporation No Drawing. Division of application Ser. No. 847,680, Get. 21, 1959. Continuation of application Ser. No. 847,679, Get. 21, 1959. This appiication May 31, 1960, Ser. No. 32,602

14 Claims. (Cl. 167-31) The present invention relates to a method for combating gastropods by utilizing the high intrinsic activity against gastropods of compositions having as their active ingredients derivatives of Z-hydroxy-benzoic-anilides. The instant application is a consolidation continuationin-part of application Serial No. 612,104, filed September 26, 1956, a continuation of application, Serial No. 847,679, filed October 21, 1959, both now abandoned, and a division of application, Serial No. 847,680, filed October 21, 1959.

It is well known that considerable amount of agricultural and horticultural damage is traceable to gastropods. In addition, snails and slugs of this order serve as hosts to many common parasites, as for example the trematodes. The transmitting host or snail releases the final free swimming larval stage of a trematode (cercaria), consisting of a body and tail, into the water where the same encyst on aquatic vegetation, in the skin of fish or in the bodies of crabs and are the infesting stage of trematodes for man and animals. The parasites enter the body via the alimentary tract by ingestion of the uncooked or insufliciently cooked fish, crustaceans and vegetation, through drinking infested water or through the skin of person or animals bathing or wading in the infested water.

Thus, it is most important from the public health standpoint not only to treat the disease entity once it has occurred, but to wipe out the gastropod and thus the source of the disease. It can be appreciated that in countries where epidemics of these diseases occur a satisfactory method of combating the gastropod invertebrate host, i.e., the snail, can be of great and special importance.

The most commonly known agent used in destroying the gastropod is copper sulfate. However, the same is not specific and additionally is not statistically effective. The use of 5,5-dibromo-salicil and pentachlorophenol has been suggested for combating gastropods. However, the same do not exhibit specificity and additionally must be used in very high concentrations.

It is an object of the present invention to provide a method for combating gastropods. It is a further object of the invention to provide a method for combating gastropods which is especially efiective with respect to snails and slugs, which invertebrate animals cause considerable agricultural and horticultural damage and which are the intermediate hosts of the trematodes and flukes, which are parasitic in man and animals.

In accordance with the invention, it has now been found that compositions which contain certain derivatives of 2-hydroxy-benzoic anilide are eiiective gastropodicidal agents. These efiective gastropodicidal agents are selected from the group of the Z-hydroxy-benzoic anilide derivatives having the formula wherein R is hydrogen or a lower alkanoyl radical having from 1 to 4 carbon atoms and which is substituted at one of the numbered positions with a halogen atom and at another numbered position with a member selected from the group consisting of halogen and the nitro group; and further members of the said first mentioned group substituted at a total of up to three additional of the numbered positions with members selected from the group consisting of halogen, methyl and trifluoro methyl, the total number of halogen substituents, however, not exceeding four and the total number of nitro groups not exceeding two.

Here and in the following, chlorine, bromine and iodine are to be understood by halogen.

A group of particularly active gastropodicidal agents in accordance with the invention have the general formula wherein R is hydrogen or a lower alkanoyl radical having from 1 to 4 carbon atoms, R is hydrogen or methyl, R is chlorine or bromine, R and R are hydrogen, methyl, chlorine or bromine, or a nitro group, R and R are hydrogen, chlorine or bromine and wherein always only one nitro group and at most three halogen substituents are present.

By Way of example of derivatives of 2-hydroxy-benzoicanilide, to which the invention relates, mention is made of the following notably useful and more or less readily producible compounds:

Melting Point, C.

5,2,5-trichloro-3-methyl-4'-nitro-2-acetoxybenzanilide 1 'The preparation of these compounds may be carried out in exactly the same way as the preparation ofsalicylanilide, i.e., by reacting the corresponding substituted salicylic acid or its derivatives with aniline or its derivatives, as described for example in Anualen der Chemie 210, 341-342; Berichte der Deutschen Chemischen Gesellschaft 22, 2907; Berichte der Deutschen Chemischen Gesellschaft 6, 336; Journal fuer praktische Chemie [2] 16, 442.

The Z-hydroxy-benzoic anilide is the essential active part or basis of the agent used to combat the gastropods. The agent may comprise a single compound or a mixture of compounds selected from the stated class. In all cases, it is assumed that the selected active ingredient or ingredients are present in an effective amount.

It will be understood that in most cases the composition also actually includes a suitable carrier in uniform admixture with the active ingredients, e.g. appropriately distributing the ingredients and facilitating application of the active agent to the surface or other locality of use, as for example for such spreading, penetrating or other special access as may be required of the active ingredients for the anti-gastropodal effect. Thus, the compounds are applied usually in combination with solid carriers, such as talc, chalk, bentonite, clay and comprise for example a dusting powder, or the compounds may be applied in combination with liquid carriers, such as water, aliphatic alcohols, especially lower aliphatic alcohols, such as methanol etc., ketones, especially lower aliphatic ketones such as acetone, methyl-ethyl-ketone etc., acetonitrile or other inert organic solvents. If applied with or'in water, salts of the compounds in their aqueous solutions may be used. Examples of salts which may be used in such solutions are the sodium, potassium or ammonium (i.e., alkali group) salts. However, the free 2-hydroxy compounds or their acyl derivatives may also be used in aqueous emulsions with any inert emulsifier, such as soaps, higher alkyl sulfonates, fatty acid esters, polyglycol ethers or esters and the like. Generally, dilutions or solutions in a concentration of 10 to 10* by weight are used, but also higher or lower concentrations may sometimes be convenient.

The agents may also conveniently be employed admixed with other pesticides, insecticides, fungicides, weed killers, fertilizers, etc. The compositions are not merely specific against certain distinct gastropods, but all snails and slugs, and generally mollusci, are destroyed effectively thereby. By way of example, there are mentioned Aizstralorbis quadelupensis, Biophalaria species, lymnaea species and Galba species.

The following are a number of specific examples of preparations which are of special value in practical application under various circumstances, as indicated. It will be understood, nevertheless, that these are simply set forth by way of example and that a variety of other combinations may be prepared, including various different combinations, of the active ingredients and likewise a variety of carrier and other supplemental materials. In all cases, .and indeed elsewhere in this specification, reference to parts or percentages are intended to mean values by weight, unless otherwise specifically indicated.

Example 1 ExampleZ OH I. l

l or

By the same way as described in Example 1, but using equimolecular amounts of. -chloro-salicylic acid and 2- chloro-4-nitro-aniline, there is obtained the 5,2'-dichloro- 4'-nitro-salicylic-anilide, melting at 233 C.

Example 3 (1)11 OzN O1 QWNHG By the same way as described in Example '1, but using cquimolecular amounts of S-chloro-salicylic acid and 2- nitro-S,S-dichloro-aniline, there is obtained the S,3',5'-trichloro-Z'mitro-salicylic-anilide, melting at 190 C.

Example 4 H3O OH Cl 1 I l By the same way as described in Example 1, but using equimolecular amounts of 5-chloro-3-methyl-salicylic acid and 4-nitro-2,5-dichloro-aniline, there is obtained the 5,2',5'-trichloro-3-methyl-4-nitro-salicylic-anilide, melting at 194 C.

Example 5 (FE CH3 Example 6 (i) H No:

By-the same way as described in Example 1,. but using equimolecular amounts of S-chloro-salicylic acid and 4- chloro-2-nitro-aniline, there is obtained the 5-,4'-dichloro- 2-nitro-salicylic-anilide, melting at, 175 C.

Example 7 (])O C CH: 01

10 grams of 5,2',5'-trichloro-4-nitro-salicylic-anilide are dissolved in 30 milliliters of acetic acid anhydride and heated for 1 hour to the boiling point of acetic acid anhydride under reflux. The reaction mixture is allowed to cool down. The crystals are separated by filtration with suction and washed with a small amount of acetic acid. The 5.,2,5' trichloro 4' nitro-Z-acetoxy-benzanilide obtained is almost pure and melts at 169 C.

Example 8 NO: a 51 By the same way as described in Example 7, but using the equimolecular amount of 5,2,5-trichloro-3- methyl-4-nitro-salicylic-anilide, there is obtained the 5, 2,,5-trichloro-3-methyl-4'-nitro 2 -,acetoxy benzanilide, melting at C;

Example 9 pounds are efiective.)

Compound I II III IV V VI VII VIII Concentration 10- 1O lO- ltH- 10- 10* 10 Example 10 Efiective compositions of two useful active ingredients are given in the following two tables, using (a) a solid and (b) a liquid composition of active ingredient and a carrier:

(a) 50 g. of 5,2',5'-trichloro-4-nitro-salicylanilide, finely divided to particles less than 5p, and 50 g. of talc. These compounds are well mixed and may be dusted as such or extended with further carriers.

(b) g. 5,2,5-trichloro-4-nitro-salicylanilide, 80 g. glycol-monobutyl-ether and 5 g. polyglycol-phenyl-ether (C C glycol chain) (Commercial emulsifier). This liquid preparation may be diluted with water and a stable emulsion suitable as an eflfective molluscicide composition obtained therefrom.

In the following, the preparation of some of the active ingredients is given without restricting the invention to these compounds given:

A suspension in chlorobenzene of 346 grams of 5- chloro-salicylic acid and 346 grams of 2-chloro-4-nitro aniline are heated to 140 C. 64 milliliters of phosphorus trichloride are dropped into the suspension and the mixture heated to 160 C. for a short period. The chloro-benzene is removed by steam distillation and the residue filtered by suction. The product obtained is sufiiciently pure for use as molluscicide. After recrystallizing from ethanol, it melts at 233 C.

Analogously:

5,2',5'-dichloro-4'-nitro-salicyl-anilide 5,4-dichloro-2'-nitro-salicyl-anilide, and 5,2',5'-trichloro-3-methyl-4'-nitro-sallcyl anilide.

We claim:

1. The method of combating gastropods which comprises applying to at least one of the gastropods and their habitat a member selected from the group of 2-hydroXy-benzoic anilide derivatives having the formula wherein R is a member selected from the group consisting of hydrogen and lower alkanoyl radicals having from one to four carbon atoms and which is substituted at one of the numbered positions with a halogen atom and at another numbered position with a member selected from the group consisting of halogen and the nitro group; and further members of said first mentioned group substituted at a total of up to three additional of the numbered positions with members selected from the group consisting of halo- 6 gen, nitro, methyl and trifiuoromethyl, the total number of halogen substituents however not exceeding four and the total number of nitro groups not exceeding two.

2. Method according to claim 1, wherein said 2-hydroxy-benzoic-anilide derivative is admixed with a carrier.

3. Method according to claim 2, additionally containing an emulsifier.

4. The method of combating gastropods, which comprises applying to at least one of the gastropods and their habitat 5,2'-dichloro-4'-nitrosalicylic acid anilide.

5. The method of combating gastropods, which comprises applying to at least one of the gastropods and their habitat 5,4-dichloro-Z-nitro-salicylic acid anilide.

6. The method of combating gastropods, which comprises applying to at least one of the gastropods and their habitat 5,2',5-trichloro-2-methyl 4 nitro-salicylic acid anilide.

7. The method of combating gastropods, which comprises applying to at least one of the gastropods and their habitat 5,2,5'-trichloro-4-nitro-salicylic-anilide.

8. The method of combating gastropods, which comprises applying to at least one of the gastropods and their habitat 5,3',5'-trichloro-2-nitro-salicylic-anilide.

9. The method of combating gastropods, which comprises applying to at least one of the gastropods and their habitat 5,5-dich1oro-2'-methyl-4-nitro-salicylicanilide.

10. The method of combating gastropods, which comprises applying to at least one of the gastropods and their habitat 5,2,5'-trichloro-4-nitro-2-acetoxy-benzanilide.

11. The method of combating gastropods, which comprises applying to at least one of the gastropods and their habitat 5,2,5'-trichloro-3-methyl-4'-nitro-2-acetoxy-benzanilide.

12. The method of combating gastropods which comprises applying to at least one of the gastropods in their habitat a composition containing as the essential efiective ingredient a member selected from the group of 2-hydroxy-benzoic anilide derivatives having the formula wherein R is a member selected from the group consisting of hydrogen and lower alkanoyl radicals having from one to four carbon atoms and which is substituted at one of the numbered positions with a halogen atom and at another numbered position with a member selected from the group consisting of halogen and the nitro group; and further members of said first mentioned group substituted at a total of up to three additional of the numbered positions with members selected from the group conssting of halogen, nitro, methyl and trifluoromethyl, the total number of halogen substituents however not exceeding four and the total number of nitro groups not exceeding two.

13. Method according to claim 12, wherein said active ingredient is in the form of its salt in solution in water.

14. Method according to claim 12, wherein said composition comprises an aqueous solution having a concentration of between 10 to 10'- by weight of said active ingredient.

References Cited in the file of this patent UNITED STATES PATENTS 2,703,301 Shumard Mar. 1, 1955 2,703,332 Bindler et a1. Mar. 1, 1955 FOREIGN PATENTS 427,270 Great Britain May 22, 1935 UNITED STATES PATENT CFFICE CERTIFICATE OF CORRECTION Patent No. 3,079,297 February 26, 1963 Ernst Sichraufstatter et a1,

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below Column 1, line 35, for "person" read persons column 4, line 74, before "acetoxy" strike out the comma; column 5, i2 the table, under the heading VIII, for "10 read 10 column 6, line 16, for '2methyl4-nitro"- read 3methyl4 nitr0- Signed and sealed this 24th day of September 1963.

(SEAL) Attest:

ERNEST w. SWIDER DAVID ADD Attesting Officer Commissioner of Patents 

1. THE METHOD OF COMBATING GASTROPODS WHICH COMPRISES APPLYING TO AT LEAST ONE OF THE GASTROPODS AND THEIR HABITAT A MEMBER SELECTED FROM THE GROUP OF 2-HYDROXY-BENZOIC ANILIDE DERIVATIVES HAVING THE FORMULA 